gWidgets2 (version 1.0-10)

gcheckboxgroup: Constructor for checkbox group. A linked group of checkboxes, but not exclusive.

Description

Change handler for a GCheckboxGroupp is called when any of the checkboxes changes state.

The svalue methods refer to the selected values. By default these are the item values, coerced to characterq. When index=TRUE is specified, then the index is returned as an integer vector. For setting, one may also use a vector of logicals (which is recycled) for the index.

Usage

gcheckboxgroup(
  items,
  checked = FALSE,
  horizontal = FALSE,
  use.table = FALSE,
  handler = NULL,
  action = NULL,
  container = NULL,
  ...,
  toolkit = guiToolkit()
)
.gcheckboxgroup(
  toolkit,
  items,
  checked = FALSE,
  horizontal = FALSE,
  use.table = FALSE,
  handler = NULL,
  action = NULL,
  container = NULL,
  ...
)
# S3 method for GCheckboxGroup
addHandlerChanged(obj, handler, action = NULL, ...)
# S3 method for GCheckboxGroup
svalue(obj, index = NULL, drop = NULL, ...)

Value

Returns an object of class GCheckboxGroup for which the following methods are overridden:

• svalue Return the selected values or an empty character vector. If index=TRUE, returns indices of selected values.

• svalue<- Set the selected values one of three ways: by label name, by a logical variable indicating which are selected (if ambigous, logical wins), if index=TRUE by the indices to select.

• [ returns labels

• [<- set the label values. Should be able to shorten or lengthen list

Arguments

items

checkbox labels

checked

logical. Are values checked

horizontal

logical. If true displayed horizontally, else vertically

use.table

logical. If supported, and TRUE then uses a table widget with scrollbars

handler

A handler assigned to the default change signal. Handlers are called when some event triggers a widget to emit a signal. For each widget some default signal is assumed, and handlers may be assigned to that through addHandlerChanged or at construction time. Handlers are functions whose first argument, h in the documentation, is a list with atleast two components obj, referring to the object emitting the signal and action, which passes in user-specified data to parameterize the function call.

Handlers may also be added via addHandlerXXX methods for the widgets, where XXX indicates the signal, with a default signal mapped to addHandlerChanged (cf. addHandler for a listing). These methods pass back a handler ID that can be used with blockHandler and unblockHandler to suppress temporarily the calling of the handler.

action

User supplied data passed to the handler when it is called

container

A parent container. When a widget is created it can be incorporated into the widget heirarchy by passing in a parent container at construction time. (For some toolkits this is not optional, e.g. gWidgets2tcltk or gWidgets2WWW2.)

...

These values are passed to the add method of the parent container. Examples of values are expand, fill, and anchor, although they're not always supported by a given widget. For more details see add. Occasionally the variable arguments feature has been used to sneak in hidden arguments to toolkit implementations. For example, when using a widget as a menubar object one can specify a parent argument to pass in parent information, similar to how the argument is used with gaction and the dialogs.

toolkit

Each widget constructor is passed in the toolkit it will use. This is typically done using the default, which will lookup the toolkit through guiToolkit.

obj

receiver object

index

NULL or logical. If TRUE and widget supports it an index, instead of a value will be returned.

drop

NULL or logical. If widget supports it, drop will work as it does in a data frame or perhaps someother means.

Examples

if(interactive()) {
  w <- gwindow("Selection widgets")
  g <- gvbox(cont=w)

  fl <- gformlayout(cont=g)
  gcheckbox("checkbox", checked=TRUE, cont=fl, label="checkbox")
  gradio(state.name[1:4], selected=2, horizontal=TRUE, cont=fl, label="gradio")
  gcheckboxgroup(state.name[1:4], horizontal=FALSE, cont=fl, label="checkbox group")

  bg <- ggroup(cont=g)
  gbutton("ok", cont=bg, handler=function(h,...) print(sapply(fl$children, svalue)))



}